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排序方式: 共有116条查询结果,搜索用时 62 毫秒
1.
Mat Rasol Awang Hassan Hamdani Mutaat Mohd. Shukri Mahmud Wan Badrin Wan Husain Tajuddin Osman Khomsaton Abu Bakar Asmahwati Kassim Zal U''yun Wan Mahmud Ishak ManafTamikazu Kume Shoji Hashimoto 《Radiation Physics and Chemistry》1993,42(4-6):611-616
In solid state fermentation, Pleurotus sajor-caju has been found to be able to degrade at least 30% oil palm empty Fruit Bunch (EFB) fibre leaving 70 % useful materials. Conditions under which fermentation carried out were investigated. It was found that, in the temperature range between 25– 28 °C, relative ph between 6–8, moisture between 60–70 % and medium composition of CaCO3: rice bran 2 %: 5 % were the optimum conditions. The results showed in fermented products that, there were substantial reduction in cellulosic component such as Crude Fiber (CF, 18 %); Acid Detergent Fibre (ADF, 45 %), Neutral Detergent Fibre (NDF, 61 %) and Acid Detergent Lignin (ADL, 14 %). However, Crude Protein (CP, 10%) increased resulted from single cell protein enrichment of mycelial microbial mass. The mass reductions of substrate in fermentation process corresponds to the CO2 released during fermentation. Hence, attributable to the decreased in content of CF, ADF, NDF, and ADL. The digestibility study has also been carried out to determine the useful level of this product to ruminant. Aflatoxin content was detected low in both the initial substrates and products. Based on nutritional value and low content of aflatoxin, the product is useful as a source of roughage to ruminant. 相似文献
2.
Peter G. Dormer Amude M. Kassim Johnnie L. Leazer Jr. Feng Xu Edward G. Corley Jimmy O. DaSilva David M. Tschaen 《Tetrahedron letters》2004,45(28):5429-5432
A general method for the preparation of syn-2,3-disubstituted-2,3-dihydro-1,4-benzoxathiin rings from 2-mercaptoethanols and quinone ketals is presented. This ring system is produced by Michael addition of a 2-mercaptoethanol to a quinone ketal, followed by cyclization of the initial Michael adduct, and subsequent aromatization to afford a syn-2,3-disubstituted-1,4-benzoxathiin in fair to good chemical yield. Several chiral syn-2,3-disubstituted-2,3-dihydro-1,4-benzoxathiin rings were prepared with this method from enantioenriched 2-mercaptoethanols. No loss of enantiopurity was observed. 相似文献
3.
A new lead(II) electrode has been constructed with poly(hydroxamic acid) (PHXA) as the active material and silicone rubber as the supporting material. The electrode gave near Nerstian response over the concentration range 4 × 10−5−1 × 10−2M lead(II). The detection limit of the electrode is approximately 4 × 10−6M and the electrode works well in the pH range 4.5–6.0. The response time was 50–120 sec over the whole concentration range and the electrode has a working life of at least 4 weeks. Iron(III) severely poisoned the electrode membrane. Nickel(II) and mercury(II) gave very strong interference compared to copper(II), silver(I), cobalt(II), sodium(I), potassium(I), zinc(II) and cadmium(II) which gave some or little interference. Values determined with atomic absorption (AAS) and a commercial lead(II) electrode were in good agreement with those measured with the lead(II) electrode reported here. 相似文献
4.
Morrow AP Kassim OO Ayorinde FO 《Rapid communications in mass spectrometry : RCM》2001,15(10):767-770
Three commercial oral rinses and one commercial disinfectant formulation were analyzed for the presence of cationic surfactants using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) in the positive ion mode. The product labels on these formulations indicate the presence of cetylpyridinium chloride, tetraalkylammonium or trialkylbenzylammonium chlorides. The resulting MALDI-TOF mass spectra only showed cetylpyridinium, tetraalkylammonium, and trialkylbenzylammonium ions, apparently due to the dissociation of the salts in the ion source. We confirmed the presence of cetylpyridinium salt in the three oral formulations, whereas the disinfectant formulation consisted of a complex mixture of the salts of dioctyldimethylammonium, didecyldimethylammonium, benzylmyristyldimethylammonium, decyloctyldimethylammonium, benzyldecyldimethylammonium, and benzylcetyldimethylammonium. This work demonstrates again the potential for using meso-tetrakis(pentafluorophenyl)porphyrin as a matrix in the MALDI-TOFMS analysis of low molecular weight compounds. This study also demonstrates that the mode of ionization of quaternary ammonium compounds (cationic surfactant salts) under MALDI conditions is by dissociation, leading to the detection of only the positively charged moieties. 相似文献
5.
1,5-Di-(2-chlorophenyl)-3-mercaptoformazan (2,2'-dichlorodithizone) has been synthesized and characterized. Its acid dissociation constant and its partition coefficient between carbon tetrachloride and water have been determined. The introduction of chlorine atoms into the ortho positions of the phenyl nuclei of dithizone was found to affect the visible electronic spectra of the reagent and its metal complexes. The ranges of pH for complete extraction, and the extraction constants, for the Hg(II), Cu(II), Zn(II), Cd(II), and Pb(II) complexes have been determined. The stability constants of the Cu(II) and Zn(II) complexes were also determined. Discrepancies between the present extensive data and the corresponding earlier data have been attributed to use of impure materials and/or inaccuracy of measurements in the earlier work. 相似文献
6.
Muhammad Saad Khan Cornelius Borecho Bavoh Khor Siak Foo Azmi Mohd Shariff Zamzila Kassim Nurzatil Aqmar Bt Othman Bhajan Lal Iqbal Ahmed Mohammad Azizur Rahman Sina Rezaei Gomari 《Molecules (Basel, Switzerland)》2021,26(2)
This study evaluates the kinetic hydrate inhibition (KHI) performance of four quaternary ammonium hydroxides (QAH) on mixed CH4 + CO2 hydrate systems. The studied QAHs are; tetraethylammonium hydroxide (TEAOH), tetrabutylammonium hydroxide (TBAOH), tetramethylammonium hydroxide (TMAOH), and tetrapropylammonium hydroxide (TPrAOH). The test was performed in a high-pressure hydrate reactor at temperatures of 274.0 K and 277.0 K, and a concentration of 1 wt.% using the isochoric cooling method. The kinetics results suggest that all the QAHs potentially delayed mixed CH4 + CO2 hydrates formation due to their steric hindrance abilities. The presence of QAHs reduced hydrate formation risk than the conventional hydrate inhibitor, PVP, at higher subcooling conditions. The findings indicate that increasing QAHs alkyl chain lengths increase their kinetic hydrate inhibition efficacies due to better surface adsorption abilities. QAHs with longer chain lengths have lesser amounts of solute particles to prevent hydrate formation. The outcomes of this study contribute significantly to current efforts to control gas hydrate formation in offshore petroleum pipelines. 相似文献
7.
Tahir Ahmad Sabariah Baharun Khairil Anuar Arshad 《Journal of mathematical chemistry》2010,47(4):1263-1273
In this paper we have investigated and explored the realm of fuzzy graph in its relation to autocatalytic sets. A new concept
namely fuzzy autocatalytic set have been defined. This relation has produced some results in the forms of theorems which have
been proven. A clinical waste incineration process has been modeled using this new concept indicates to be more accurate than
using crisp graph. 相似文献
8.
9.
Santos Regis C. Maia José R. da S. Abras Anuar Filgueiras Carlos A. L. 《Hyperfine Interactions》2002,142(3-4):495-501
Several novel tin(IV) adducts of amidines, [SnClPh3L], [SnCl2Ph2L] and [SnBr4L] {L=N,N-diphenylacetamidine (Hdpac) or N,N-diphenylbenzamidine (Hdpba)}, were prepared and investigated by Mössbauer spectroscopy which was an important tool for the elucidation of bonding and structural features. The resulting Mössbauer data also led to the conclusion that the tin(IV) centre for the adduct [SnClPh3L] is pentacoordinated in a trigonal bipyramidal arrangement and hexacoordinated for [SnCl2Ph2L] and [SnBr4L] in a geometric patterns of an octahedral. The amidines act as monodentate ligands to the metal centre for the former and bidentate for the latter. 相似文献
10.
One advantage which is often claimed for extraction operations carried out with near-critical extractants is that higher mass transfer rates may be obtained than with normal liquid extract. Although there is circumstantial evidence that this is the case, quantitative information is scarce.
On-going work at Birmingham which is directed towards the measurement of mass transfer rates into near-critical fluids and also the measurement of the associated phase equilibrium properties is described. Some new results are given, although the rate data presented are regarded as preliminary only. The extractant principally considered is carbon dioxide. 相似文献